|
![](/i/fill.gif) |
In article <3976fd4b@news.povray.org>, "Luke Church"
<Luk### [at] church karoo co uk> wrote:
> I have a cylindrical shape that contains an emission media, however I
> wanted to vary the density, so that it decayed exponentially
> (preferably but linear would do) as it approached the edge of the
> shape, after several hours trying to play around with it I though I
> would ask for help.
Try the poly_wave waveform:
density {cylindrical poly_wave 2
color_map {
[0.0 rgb <1, 0, 0>]
[0.5 rgb <0.5, 0, 0.5>]
[1.0 rgb <0,0,1>]
}
}
You could also adjust the color_map to get close to the same effect, but
it would be more difficult.
> A second question I have is as to the interaction between media,
> radiosity and animations. Will either media or radiosity produce a
> 'gitter' effect that is caused by random sampling, e.g. jitter and/or
> crand keywords?
In the official version, radiosity currently doesn't work well with
media. Specifically, the radiosiy samples never enter the container
object, and media isn't calculated for the radiosity samples. MegaPOV
fixes this, and these changes will probably make it into the next
official release.
As for the "gitter" effect...were you trying to type "glitter" or
"jitter"? Oh, well...both media and radiosity can produce random
effects, though these can be minimized with certain settings. This is
easier to do with MegaPOV radiosity and media method 3...with the
official version, you basically have to increase your samples and adjust
variance and confidence until the "grainyness" isn't visible enough to
be a problem. This can be very slow...though emitting media is probably
the fastest.
I don't have any experience with radiosity, so I can't help you there.
> PS - Damned Outlook Express has converted my comments into ftp links -
> please ignore them!
You can get around this by using "// comment" instead of "//comment".
The extra space after the slashes keeps it from happening.
--
Christopher James Huff - Personal e-mail: chr### [at] mac com
TAG(Technical Assistance Group) e-mail: chr### [at] tag povray org
Personal Web page: http://homepage.mac.com/chrishuff/
TAG Web page: http://tag.povray.org/
Post a reply to this message
|
![](/i/fill.gif) |